Radar scanner unit



Aug. 16, 1949. T. 1. MOSELEY 2,479,539

' RADAR SCANNER UNIT Filed June 25, 1946 8 Shegts-Sheet 1 '3 INVENTOR.

750M500! Mair/r Aug. 16, 1949. "r. MOSELEY RADAR SCANNER UNIT 8Sheets-Sheet 2 Filed June 25, 1946 D INVENTOR. 750700500 1: Mose/q Aug.16, 1949 T. a. MOSELEY RADAR SCANNER UNIT 8 Sheets-Sheet 5 Filed June25, 1946 INVENTUR. /5/27// 75m Z Max 8y BY ATTUE/Vffi 19494 T. 1.MOSELEY 2,479,535

RADAR SCANNER UNIT Filed June 25, 1946 8 Sheets-Sheet 4 Fig. 4

I INVENTOR. 75/77///750/7 f Masc/qv T Aug. 16, 11949.. T. l. MOSELEY 9?RADAR SCANNER UNIT Filed June 25, 1946 8 Shets-Sheet 5 Fig. 5

I Z 20/202 ,j/" l ATTOE/VEKF Aug. 16, 1949. 'r. MOSELEY ,5

RADAR SCANNERQUNIT Filed June 25, 1946 8 Sheets-Sheet 6 .INVENTOR.7507/0250 [Nose/Ly Aug. 16, 1949. T. 1. MOSELEY 2,479,539

RADAR SCANNER UNIT Filed June 25, 1946 8 Sheets-Sheet 7 Fig. 7

IN V EN TOR. Emfihsm j. Mose/9y Aug. 16, 1949. T. LMOSYELEY RADARSCANNER UNIT Filed June 25, 1946 8 Sheets-Sheet 8 INVENTOR. Exp/M500[Mose/g 'ATTOP/VEKF Patented Aug. 16, 1949 UNITED STATES PATENT OFFICERADAR SCANNER UNIT Tomlinson I. Moseley, Atherton, Calif.

Application June 25, 1946, Serial No. 679,120

18 Claims. 1

This invention relates to radar equipment including a radio frequencyreflector arranged to scan a predetermined zone and constitutes animprovement to the radar scanning unit disclosed in my co-pendingapplication Serial No. 672,462, filed May 27, 1946.

The unit disclosed in my said co-pending application includes areflector arranged continuously and progressively to scan a conical zoneof a predetermined and selected solid angle.

In general the object of the present invention is the provision of ascanner unit arranged for line or azimuth scanning as well as forconical scanning.

More specifically the object of this invention is the provision of aradar scanning unit including a reflector arranged selectively fornodding or for simultaneous rotation and nodding.

A further object of this invention is the provision of a scanning deviceincluding a reflector swiveled on the end of a. spindle Journaled in aframe; reciprocating means for imparting a nod to said reflector; and areversible motor for driving said reciprocating means upon rotation ofthe motor in either direction and for rotating said spindle through a,clutch mechanism only in one direction.

Still another object of this invention is the provision of a radarscanner including a reflector and feed horn swiveled on a. spindleselectively for nodding or for simultaneous nodding and rotation andprovided with means for returning and maintaining said reflector andfeed horn to and in a predetermined angular position with respect to thecommon axis of these members preparatory to and during a, noddingoperation in the absence of rotary movement thereof.

The invention possesses other advantageous features, some of which withthe foregoing will be set forth at length in the following descriptionwhere that form of the invention, which has been selected forillustration in the drawings accompanying and forming a part of thepresent specification is outlined in full. In said drawings, one form ofthe invention is shown, but it is to be understood that it is notlimited to such form, since the invention, as set forth in the claims,may be embodied in a plurality of forms.

Fig. 1 is a perspective view of a radar scanner embodying the objects ofmy invention.

Fig. 2 is a side elevation of the scanner illustrated in Fig. l withportions broken away better to illustrate its construction and with itsreflector assembly shown in a full nod position.

Fig. 3 is a longitudinal horizontal mid-section of the scanner shown inFig. 1 except for the reflector and generator which are shown in plan.

Fig. 4 is a partial vertical mid-section of the scanner illustrated in 1particularly showing the construction of its main gear housing, spindlehousing, reciprocating rack sleeve and pinion, and rack sleeve drivingmechanism.

Fig. 5 is a rear end elevation of the scanner with portions broken awaybetter to illustrate the construction of its air pump.

Fig. 6 is a rear end elevation similar to that illustrated in Fig. 5 butshowing in section the mechanism by which reciprocating motion isimparted to the rack sleeve from the gear train.

Fig. 7 is an interior view of the gear train looking rearwardly, withthe gear housing removed and with portions of the gears broken awaybetter to illustrate its construction.

Fig. 8 is a schematic top-plan view of the rack sleeve and oscillatingmechanism, the potentiometer drive and solenoid stop mechanismi Thescanner shown in the various figures above described includes a gearhousing I, to which is bolted a housing cover 2 and a clutch unitbracket 3, all of which constitute a frame for the scanner.

Mounted on the housing cover 2 is a. reversible twenty-six volt motor 6,and a two-phase, twentycycle generator 1 (Fig. 3). Mounted on the clutchbracket 3 is a clutch unit 8, a solenoid 9, a potentiometer II and anair pump 12, and supported by the pump is an air filter and dehydratorl3.

Journaled for rotation within the housing I on ball bearings l4 and I5is a forwardly diverging and flanged main spindle IS, the spindle beingsealed to the housing cover 2 by a seal ring l1, and to the housing I bya seal ring 18. Screwed to the main spindle I6 are a plurality ofperipherally spaced balancing washers [9 by which the spindle and itsassociated parts can be brought into dynamic balance. Screwed over theforward end of the spindle I6, is a bearing retaining ring 20 andprovided in the housing I adjacent to and communicating with the ballbearing I5, is a lubricating nipple 2|.

The housing cover 2 is formed with a forwardly extending boss 22 inwhich is mounted a pair of ball bearings 23 and 24, held in place by aretainer 25 (Fig. 4). Mounted in the ball bearings 23 and 24 is theshaft 26 of a motor drive pinion 21, the rear end of the shaft 26 beingkeyed to the forward end of the motor shaft 28. Surrounding the rearwardend (left hand end as 3 shown in Fig. 4) of the shaft 26 is a seal ring29 for sealing the shaft to the housing cover.

Fastened to the left end of the spindle I6 by a key 3| is a gear sleeve32 provided on its left end (as viewed in Fig. l) with a pinion gear 33.Formed around the sleeve 32 to the right of the gear 33, is an annularchannel 34 for the reception of a pair of semicircular wedged shapedmembers 35 and 26. Disposed beneath the members 35 and 36 within thechannel 34 is a split marcelled spring 31.

The opposite or large ends of the members 35 and 36 are located adjacenteach other and are pivoted to the sleeve 32 by pins 38 and 39. Thesmaller or tapered ends of these members are therefore free for limitedradial movement within the channel 34 against the action of the spring31.

Surrounding the sleeve 32 and rotatable thereon against the action ofthe wedge shaped members 35 and 36, is a clutch drive ring gear 4|.Fastened to the ring gear 4| by a key 42 is a main drive gear 43 in meshwith the motor drive pinion 21 and provided with a boss 44 extending tothe right as shown in Fig. 4.

Seated over the left end of the pinion gear 33 is a washer 45 andthreaded on the left end of the spindle I6 is a nut 46 serving to lookits associated gear assembly in place.

In view of this construction it will be noted that the pinion 21 drivesthe main drive gear 43 and that the spring loaded semicircular wedgeshaped members 35 and 36 serve as a light friction brake or drag betweenthe gear 4| and the gear sleeve 32 regardless of the direction oftotation of the pinion 21.

Formed on the right end of the gear sleeve 32 is a ratchet wheel 41provided with teeth 48. (See Fig. 7). Pivoted by a pin 49 to the boss 44of the main drive gear 43 and within a recess is a pawl 52 provided witha detent 53 arranged to engage one of the teeth 48 when the gear 43 isrotating clockwise as viewed in Fig. '7. Also formed on the pawl 52 is alug 54 for anchoring one end of a coil spring 55, the opposite end ofthis spring being fastened to the gear 43.

Fastened to the gear housing 2 by a counter sunk Allen screw 56 is aslide bed 51 provided at its upper edge as viewed in Fig. 1 with anupstanding flange 58. Slidably disposed on the bed 51 is a slide stop 59formed with a slot 6| and provided with an upstanding flange 62. Theupper end of the flange '62 is undercut and overhangs the right end ofthe flange 58. Extending through the slot BI and threaded into the bed51 and the housing 2 is a fiat headed guide pin 63. Also threaded intothe bed 51 and the housing 2 is a screw 64 provided with an eccentrichead 65. The left side of the head 65 engages the curved lower side 66of the slide stop 59 and consequently the position of the slide stop 59can be adjusted 'by rotating the head 55 to any predetermined angularposition.

Fastened to the housing 2 by an Allen screw 61 is a spring retainer 68and mounted therein is a leaf spring 69. The intermediate position ofthe spring 69 is fulcrummed over a circular projection 1| formed on themarginal flange 12 of the housing 2 and it free end engages the leftside of the stop slide 59. The spring 69 therefore resiliently opposesany movement of the stop slide 59 to the left as viewed in Figure '7.

Formed in the housing cover 2 in alignment with the generator 1 is aboss in which is mounted a pair of ball bearings 16 and '11-and ournaledin these bearings is the hollow shaft 18 of a generator drive gear 19,the shaft 18 bemg keyed to the shaft 8| of the generator 1. Accommodatedwithin a counter-sink 82, formed in the left face of the housing cover2, is a seal ring 83, by which the hollow shaft 18 is sealed to thehousing cover 2. The gear 19 meshes with the pinion gear 33 and istherefore driven by the motor 6 through the main gear 43 and the pinion21.

In mesh with the pinion 4| is a clutch drive gear 84 mounted on a hollowshaft 85, the shaft 85 being journaled in a pair of ball bearings 86 and81 mounted in a boss 88 extending forwardly of the housing cover 2.Secured over the forward end of the boss 88 is a ball bearing retainer89. Keyed to the hollow shaft 85 is a worm gear shaft 9| journaled in apair of longitudinally spaced ball bearings 92 and 93, the ball bearingsbeing mounted in a longitudinally extending chamber 94 formed in theclutch housing 3. Disposed between the chamber 94 and the shaft 9| is aseal ring 95, and closing the left end of the chamber 95 as viewed inFig. 4) is a cap 96 bolted to casting 3 by means of bolt 91. Providedintermediate the ends of the shaft 9| is a worm gear 98, the function ofwhich will be presently described.

Now momentarily referring back to Fig. 7 and the slide stop 59 and itsassociated assembly previously described:

Pivoted to the generator drive gear 19 adjacent its periphery and by apin IBI is a stop arm I92. Fastened between a pin I83 secured to thegear 19 and the upper end of the arm I02 (as viewed in Fig. 7) is aspring I64 serving resiliently to urge the lower end of the arm I02outwardly in alignment with the flange62 of the slide stop 59. it willbe seen that as a result of this construction the generator drive gear19 is free to rotate counter-clockwise in so far as the stop arm I02 isconcerned for when rotating in this direction the lower end of the armI02 is permitted to pass over the flange '62 due to the yield of thespring 194. However the clockwise rotation of the gear 19 is yieldinglyarrested by the engagement of the lower end of the stop arm I92 with theflange 62 and the limited movement of the slide stop 59 against theaction of the leaf spring 69. As will be explained later in greaterdetail, the ultimate function of this assembly is to bring the feed hornof the scanner into a predetermined and selected position preparatory toefiecting a line or azimuth scan.

Bolted to the right end of the main spindle I6, is a head pivot bracketIII, in which is mounted a pair Of transversely spaced ball bearings H2and H3 and to which is screwed a plurality of balancing washers I I4symmetrically disposed about its periphery. Journaled in the bearingsI12 and H3 is an oscillating pinion sleeve 5 provided on its peripherywith a pair of transversely spaced pinions H6 and H1. Disposed withinthe sleeve I I5 and having a force fit therewith is an oscillating jointbody I I 8, provided with an antenna feed connection H9, extendingforwardly through an opening I2I, formed in the sleeve H5, along theaxis of the main spindle I6. Fixed to the sleeve II5 by forwardlyextending ears I22 is a U-shaped head bracket I23 to which is bolted aparabolic reflector I24, and bolted to the reflector I24 coaxiallytherewith and to the connection H9 is the base I25 of a feed horn I26.The feed horn I26 terminates in a cup 12-1 provided "on its rear facewith apair of opposed windows through which a radio frequency wave orsignal can pass to and from the reflector. It should be particularlynoted that the legs I28 of the U-shaped bracket I23 extend rearwardly ofand on either side of the oscillating tube body H8 and are provided witha plurality of balancing washers I29 (Fig. 3) so that the entireoscillating assembly can be brought into dynamic balance about itscenter of movement.

Mounted in the rear face of the clutch bracket 3 (see Figs. 3 and 4)over a gasket I3I is a bearing housing I32 in which is seated a ballbearing I33. Journaled in the bearing I33 is a collar I34 over which isseated a mating ring I35 for an oil and air seal I36. Fixed to the rearface of the bearing housing I32 and sealed with the oil and air seal I36is a right angle wave guid connection I31 for connecting the scannerwith a. suitable source of radio frequency energy. Disposed across theconnection I31 is a resonance ring I38 and screwed in its rear wall is atuning button I39.

Secured within the sleeve I34 is the rear end of a wave guide tube I4Ihaving its forward end secured and sealed to the inner end of a gooseneck wave guide fitting I42 (Fig. 3). The outer end of the fitting I42is sealed to the oscillating tube body H8 and head pivot bracket I II bya seal ring I43. Screwed to the fitting I42 along the axis of the waveguide tube MI is a tuning button I44 and extending across its outer endis a resonance ring I45.

From the above description it may be seen that a radio frequency energywave or signal initiated from any suitable source can be made totraverse the wave guide connection 1 31, the wave guide tube I4I, thegoose neck fitting I42, the oscillating joint body I I8 and the feedhorn I26. The antenna cup I21 directs the wave rearwardly to thereflector I24 which then reflects the wave outwardly in a divergent beamhaving a solid angle of about 6. When the scanner is on target thereturning echo wave or signal is picked up by the reflector andtraverses in reverse, the path above described. During operation, thetube I4I,

fitting I42, tube body H8, 9. reflector I24, feed horn I26, and cup I21all rotate as an integral unit with the main spindle I6 which, as abovedescribed, is rotated by the motor 6 through the pinion 21 and the maingear 43. However, since the pinion sleeve H is journaled in the headpivot bracket I I I and since the reflector I24 and feed horn I26 areformed as integral units with the sleeve I I 5, the reflector I 24 andfeed horn I26 in addition to being free to rotate about the axis of themain spindle I6, are free to oscillate or nod about the axis of pinionsleeve II5. By oscillating these members through a plane angle of 60 oneither side of the spindle axis, and simultaneously rotating them aboutthe spindle axis, the 6 radio frequency energy beam can be madecontinuously and progressively to scan a solid angle of 120, four timesduring each complete nod cycle.

Oscillation or nodding of the reflector and its associated parts iseffected through a reciprocating mechanism including a rack sleeve I46having a sliding fit over the wave guide tube MI and with which thesleeve I46 rotates. Secured to the forward end of the sleeve I46 on oneside thereof is a pair of longitudinally extending laterally spacedracks I41, one in mesh with each of the transversely spaced pinions H6and H1 carried by the pinion sleeve I I5. To balance the weight of theracks I 41, the sleeve rack is provided on its side diametricallyopposite the racks I41, with a pair of laterally spaced balancingmembers I48 (see Fig. 4). The reciprocation of the sleeve rack with itsracks I41 in mesh with the pinions H6 and H1 therefore produces therequired oscillation of the reflector I24 and its associated parts.

Disposed over the left end of the sleeve rack I46 (Figs. 1, 3 and 4) isa thrust bearing housing I49 provided with a laterally extending slidelug I 5| and with an opposed forked guide receiver I 52. Fixed to thesleeve rack I46 in abutment with a shoulder I53 formed thereon is athrust bearing race I54 and abutting the race I54 is a sleeve I 55.Mounted on either side of the race I 54 and having running contacttherewith are looking rings I56 and I51 and located between these twolocking rings is a spacing ring I58. Dis posed on either side of therings I56 and I51 are gaskets I59 and I6I, the assembly so describedbeing held together by a split locking ring I 62.

Seated in the forked guide receiver I52 (Fig. l) is a guide bushing I63slidably mounted on a guide rod I 64, extending between and secured tothe main housing cover 2 and to the rear face of the clutch bracket 3.

Bolted to the side face of the clutch bracket 3 (see Figs. 3 and 6) is apotentiometer bracket I65 formerd with an undercut runway or channel I66and provided on the lower face of its rear end with an upwardly recessedpotentiometer seat I61 (Fig. 5) to which the potentiometer II is bolted.Slidably mounted in the channel 466 is a potentiometer slide rack I68,and bolted to the forward end of this slide rack is the slide lug I5I(Fig. 3). Mounted on the potentiometer rack I63 is an upwardly extendingconnecting rod pin I69 on which one end of a longitudinally adjustableconnecting rod I1I is journaled (Fig. 3). Secured to the opposite end ofthe connecting rod by a pin I12 is a crank I13 (Fig. 6) mounted on thelower end of a clutch shaft I14 of the clutch unit 8.

As shown in Fig. 6, the clutch unit 8 includes a housing I15 provided atits upper end with a flange I16 by which it is bolted to the clutchbracket 3. Mounted in the upper and lower ends of the clutch housing I15are ball bearings I18 and I11 by which the clutch shaft I14 isjournalled in the clutch housing, the bearing I11 being seated againstan internal flange I 18. Seated on the upper face of the flange I 18 isa seal ring I19. Journaled on the shaft I14 somewhat below its upper endis a worm gear I8I arranged to mesh with and be continuously driven bythe worm 98 formed on the shaft 9I (Figs. 2, 4 and 6). Screwed to theupper face of the Worm gear I8I is a friction cone I82 and slidablykeyed to the upper end of the shaft I14 is a conical clutch plate I83.Threaded over the upper end of the shaft I14 is a nut I84 and disposedbetween the nut I84 and the upper face of the clutch plate I83 is aspring I85 for continuously holding the clutch plate in frictionaldriving engagement with the friction cone I82.

As a result of the construction just described it Will be seen that theworm 98 is driven by the motor 6 through the motor drive pinion 21, thepinion gear 4| and the clutch drive gear 84; that the worm 98continuously drives the worm gear I 8I and that unless there is slippagebetween the friction cone I82 and the clutch plate I83, the rotation ofthe worm gear I8I will be imparted to the shaft I14 and to the crank I13carried on its lower end. Through the action of the connecting rod I",the rotary movement of the crank Hit-is translated: into areciprocatory-moves ment: of the potentiometer rack I68: and the. thrustbearing housing I49: to. which. ity is at..- tached. Since the sleeverack I46 is-fiXedf to the housing L49 it will. reciprocate with thepotentiometer rack to. cause the reflector I24. and its associated partsto nod or oscillate as.- above explained. while on search for a target.

Sometimes it is desirable to limit scanning; to a. relatively smallsolid angle in. the order of This result is produced by locking thepotentiometer sliderack I68. against further reciprocation in such aposition that the reflector I24 is held at an angle of about 3 ofi theaxis, of rotation. To this end the solenoid 9 is provided with a softiron. plunger I86 normally held in its. elevated position by a springI81 (Fig. 6). Mounted on the upper face I88 of the solenoid is a.-bifurcated bracket I89 on which is fulcrumed a latch or stop lever I9I,the inner end of the stop lever being provided with a slot I92 for thereception of. a pin I93 carried by the forked upper end of the solenoidplunger. Normally the free end of the stop lever I9I is in its depressedinactive position. However when the solenoid coil is energized, theplunger I86 is drawn downward, thereby causingthe free end of the stoplever to swing upwardly into engagement with the rear endof the sliderack I68 and to thereby limit its stroke and the amplitude of nod. ofthe reflector I 24. It. is. to be noted that when this occurs slippagetakes place between the friction cone I82 and clutch plate I83.

The potentiometer slide rack I88. in addition to imparting reciprocatorymovement to the rack sleeve I46 is arranged to mesh with a pinion I94(Fig. 8) fixed to the potentiometer shaft I95. Mounted on the shaft I95are a pair ofv diametri: cally opposed coplanar and electricallyindependent potentiometer arms I99 and I91, arranged respectively totraverse over electrically inde-v pendent resistance windings I98 andI99. Each of. these windings subtends an angle of 170 and each of thecontact arms travels overan arc, of

160?, corresponding to the full 120 nod travel of the reflector.Although per se, the electrical circuit associated with scanner nowunder. con.- sideration forms no part of the present invention, itshould be notedthat the contact arms I9 B..and I91 traverse (back and.forth) their respective potentiometer windings I98 and I99 insynchronismwith the nodding of the reflector I24; that one of, these windingsconstitutes an elevation section and the other an azimuth section, andthat by connecting the potentiometer across both phases of the two-phaseenerator 1, the posh tion of the contact arms I96 and I91 can be made todetermine the amplitude of these phases. As is known in the art by meansof a suitable receiver-amplifier unit this electrical informationcan beinterpreted and presented visually on the face ofan indicator tube orscreening so as to indicate the relative elevation and azimuth of thereflector with respect to its frame and the airplane on which it ismount d atthe instant that the echo. signal is received.

Preferably .the wave guide system. or conduit including the guide tubeMI, and'its associated fittin s ld maintained. under. a clean and dry,norma m spheric pre sureso t prevent electrical breakdown when theaircrafton. which thescanner ismounted, is operating lnhigh altie tudes.To insure this, a reciprocatingpump (Fig 5) generally designated bythereference numeral IZr-and including. a cylinder. h is mounted 0.11

the upper face 05- the clutch bracket. 3. Open atively: disposed:within. the cylinder 2M: is. a piston m to. which is; secured: a.connecting rod 203. Journaledzin a bearing housing 211 1. by means ofball: bearings: 285 and; 206'. is a shaft 201', tothe upper end oilwhich. is. secured a crank 208; the free end; ofthe connecting rod 203being journaled to a pin 299E mounted on the outerend of the crank 208.Eastenedt tothe lower end of theshaftmliisa worm gear-M I arranged tomesh with. and be driven. by thewormgear I81 (Fig: 6) whichai-n turnisadri-ven bythe worm-981f0rmed on the shaft 91 (Fig. 2). Mounted overthe outer end of: pumpcylinder 2911isa pressure chamber 212: provided:-with. a spring loaded outwardly opening check valve setto open atnormalatmosphericpressure. Gommunicating with the pump intakeiszthe-airfilterand; dehydrator I3 (Figs. 1 and 6 having: an. intake:provided with a suitable inwardiyopening spring-loaded check valve...The. pump. discharge communicates through a line 2I3 with the wave guideconnecrtion For the n rposecfimounting: the scanner unit above describedon: thenacellezof. an airplane and for adjustin it: for elevation. and;azimuth the main. housim I is; provided with opposed. later.- ally: exendin trunnion. sins 2,-1.4 and 215. (see Fi 5 which: Qarruthemaimoadorrt s n h and the. clut h bracket. :3 s p ovi ed wi ha: brach t 2L5.Figs. 1L and. .12.): meantime a suitable altitude adjustment mechanism;111,. for here,- sishting. Azimuth ad ustment inshore-si h n canr eprovide ion in confirm t on w th o Q thellate a trunn on 9i l andiilfi nanineson w thl u ab e m w-atria brac ets pm m the. 11595 16 t eversibmet n .6 oper e at 2 t-i=- v or minus 3.5 volts and, delivers. power tothe s n er-at 6 0 3 B- 111 9 i u a. B. M allow v ry n .ir m 0 o 0. w ttand preferably. should hero;- the ball bearing, air.-cpoledmontinuousdutsr. type. At normalambient tempe res .-PI ,@l1 ;Y=fl- E t mo e draws between. 20. and 28. amperes. and should drive thescanner atanproximately. 1,200. R. P. M. and i5: nod cycles per minute.

Conveniently the reflector I-Zdcanbemadc. l7 inches. in diameter with afocal length of 52/ inches. and preferably is. driven at. a speed. ofL29 B0 M.

In operatiomradio frequency microwayespass forwardly hroug e sub t aair-tigh wave,.-.conduit or wave-guide. and emerge. irom theopposedwindows-on the lower face .of-thefeed nornicun 121, as. ingsoielectricenergy with as.- so-eiated magnetic, lines. The emergingmicro.- wave energy isrefiected. from thedishor reflector 24. in. suchamanner. thatthe ays. form acone c n e imais v 5 -..an 1 W the c n 1".iscn .targetthe echowave s Rickedup by-the reflector and then, asalreadyexplained; traverses inreverse, he path .followed by, th outg n wve in passing through the wave-guide.

Conical. scanning (simul aneous rotation. and noddingor the. reflector.I24) as. distinguished from line or, azimuth. scanning (nodding only)is. effected. by so rotating the. reversible. main drive motor that. thedrive pinion 21 as viewed in Fig. 7, revolves counterclockwise. Whenre.- uolying, in..this., direction the. main drive. gear. 43 revolves:clockwise .with thedetent 5;, of, its .pawl 5.2. in drivin n aeementwi h.onepfr the ratchet teeth 48- 0. f:' the ratchet heel. A]. Since theratahe wh etflris ermedantsra w mth searsleeve 32 which in turn is keyedto the spindle l6 counter clockwise rotation of the motor 6 will causethe spindle l6 and the reflector I24 and its associatedparts to rotateclockwise (as viewed in Fig. 7).

since the main drive gear 43 is keyed to the ring gear H which in turnis always in mesh with the clutch drive gear 84, a clockwise rotation ofthe motor 6 serves to actuate the reflector nodding mechanism, to rotatethe reflector I24 and to actuate the generator 1 and the potentiometerll all as above described.

Line or azimuth scanning is effected by rotating the motor 6 clockwise,so as to revolve the main drive gear 43 and its associated ring gear 4|counter clockwise. The centrifugal force developed by the rotation ofthe main drive gear 43 forces the detent 53 of the pawl 52 (mounted onthe gear 43) out of driving engagement with the ratchet wheel 47(attached to the spindle l6). Although when this occurs there no longerexists any positive driving engagement between the main drive gear 43and the spindlev I 6, the drag produced on the spindle by the springloaded wedged shaped members 35 and 36 is sufficient to rotate thespindle l6 and its associated generator drive gear 19 through at leastone complete revolution. Thegenerator drive gear rotates clockwise andin so doing causes the lower end of the stop arm I 02 (Fig. '7) tocontact the spring loaded slide stop 59. Since the gear 19 is always inmesh with the pinion gear 33 and since the pinion gear 38 rotates withthe spindle is, the final position of the gear 79 (as determined by theslide stop 59) determines the angular position at which the feed hornI26 and its associated cup I 21 come to rest. This function of thedevice is essential for the reason that during azimuth scanning theradio frequency energy should emanate from the reflector I 26 invertical planes. As is well known in the industry the rear face of thecup I21 is provided with a pair of parallel elongated and diametricallyopposed windows through which the radio frequency energy passesrearwardly to the reflector I26. The disposition of the plane of radiofrequency energy can therefore be determined by properly positioning thereflector and its cup relative to thegear 19.

During conical scanning the potentiometer and the generator are both inoperation and serve as above outlined to indicate the position of thetarget on a screen or other device.

During azimuth scanning the generator is'inactive although thepotentiometer remains in operation for the clutch drive gear 84 isalways in mesh with the ring gear 4| which in turn is keyed to the maindrive gear t3. During azimuth scanning a suitable D. C. voltageis'supplied to the potentiometer by equipment associated with thescanner unit but thereof.

From the above description it will be observed that I have provided ascanning unit wherein the reflector assembly and its rotating andoscillating mechanism can be readily brought into dynamic balance;wherein the amplitude of nod of the reflector can be limited when thereflector is on target; wherein the wave guide conduit can be maintainedunder any desired gaseous pressure; wherein means including apotentiometer and a generator driven in synchronism with the reflectoris provided by which the altitude and. azimuth of the reflector withrespect torthe scanner frame can be determined; and which depending uponthe direction of rotation of the not forming anintegral part main drivemotor can be made selectively to effect either a conical scan or simplyan azimuth scan.

I claim:

1. A scanning unit comprising: a frame; a spindle journaled in saidframe; a gear journaled on one end of said spindle for rotation on anaxis perpendicular to the axis of said spindle; a parabolic reflectorfixed to said gear and provided with a feed horn extending alongthe axisof the reflector; a wave guide communicating with the base of said feedhorn; a rack sleeve mounted within said spindle for reciprocatorymovement with respect thereto, said sleeve being provided with a rack inmesh with said gear; a potentiometer mounted on said frame and includ-'ing a pair of resistance-coil sectors and a pair of contact armsarranged to traverse said sectors; means responsive to the movement ofsaid rack sleeve for oscillating said contact arms; a generator mountedon said frame; and means selectively for simultaneously rotating saidspindle, reciprocating said sleeve and driving said generator or forreciprocating said sleeve without rotating said spindle and generator.

2. A scanning unit comprising: a frame; a spindle journaled on saidframe; a gear journaled on one end of said spindle with'its axisperpendicular to the axis of the spindle; a parabolic reflector fixed tosaid gear for bodily movement therewith; a feed horn mounted on saidreflector along the axis thereof; a rotatable, longitudinally slidablerack sleeve mounted on said frame and extending through said spindle,said sleeve beingprovided with a rack arranged to mesh with andosoillatesaid gear on the axis thereof; a wave guide tube extendingthrough said sleeve and communicating at its forward end with the baseof said feed horn; a potentiometer mounted on said frame and including apair of resistancecoil sectors and a pair of oscillating contact armseach arranged totraverse one of said sectors; means responsive to'thesliding movement of said rack sleeve for oscillating said contact arms;a two-phase generator in'electric circuit with said resistance-coilsectors; and means selectively for simultaneously rotating said spindle,reciprocating said rack sleeve and driving said generator or forreciprocating said rack sleeve without rotating said spindle and withoutdriving said gen erator.

3. A scanning unit comprising: a frame; a

parabolic reflector swiveled to said frame for rotation about a firstaxis and simultaneous oscillation about a second axis intersecting saidfirst axis at right angles thereto; a feed horn fastened to the apex ofsaid reflector along the axis thereof; a wave guide tube communicatingwith the lower end of said feed horn; a pinion fixed to said reflectorcoaxial with said second axis; a mounted on said frame in mesh with saidpinion for reciprocatory movementalong a line parallel with said firstaxis; a potentiometer and a twophase generator mounted on said frame,said potentiometer being in electrical circuit with said generator so asto control the amplitude of both of its phases; means for bodilyrotating said reflector on said first axis and for simultaneouslydriving said generator in sync-hronism therewith; means forreciprocating said rack either with or Without the rotational movementof said reflector; and means responsive to the movement of said rack foractuating said potentiometer.

4. A scanning unit comprising: a frame; a

without driving said rack QAWQQA Iii spindle journal'ed in said traineea. reflector swivel ed to one end: of said spindle tor osciltation aboutan axis at right angles to the axis of spindle; means including areciprocating rack for oscillating said; reflector; means including areversible motor for reciprocating said rack ro sponseto: the rotation:of said motor in either directinrr; and means. including said motor anda, clutch for rotating said spindle in one direction in. response to.the rotation of said motor in OHGLKHP' rections, said clutchautomatically interrupting the drive between saidi motor and; spindle inre.- sponse to? rotation of said:v motor in: the opp site: direction.

A scanning unit comprising; a frame; a spindle journaled in saidframefor rotation about a, first. axis a reflector swiveled to one endof'said spindle for oscillation about a second axis; means including areciprocating rach supported by saidispind'le for oscillating saidreflector about said: second axis; a reversible motor, a'potentiometerand a. generator mounted on said; frame; means including a. clutch andsaid motor for retati-ng: said spindle and: for driving; said generatoruporr the rotation of said; motor in one direction means including saidmotor for reciprocatingsaid rack: andv for actmating. said potentiometerin response to. the rotation of said motor in either clirectiom saixzl.clutchr automatically interrupting the drive. fromsaidimotortolsaidlspmdtl'e and gem. eraitor upon rotation of said motorin the opposite direction 61. A scanning unit.- comprising: a frame; aspindle; iournalect in said; frame for rotation about. a first axis a.reflector swiveled to one end: of said. spindle for oscillation about a,second; axis; means including a. reciprocating rack: supported by; said:spindle for osci-li'ating: said; reflector about said: second axis;arresversiicie motor; a potentiom eter and a generator mounted on. said:frame; means; including a. clutch and saidl motor for rotatisngSBi-dlSlZil'ldlB and for driving said generator only upon the; rotationof said motor one direcs trons; means. operatin'e upon the rotation ofsaid motonin the opposite direction: for returningsaid spindle to a.predetermined angular position with respectto a fiducial: planeincluding the axis of said spindle; and means including saidmotor foractuating said potentiometer; I-GGiDIOCHzfilTIg said rack in response tothe rotation of said motor in either direction.

'7. A scanning unit comprising: a frame: aspindle journaled in saidframe for rotation on its own axis: a gear iournaled on one-end of saidspindle with its axis intersecting the spindle axis at right anglesthereto; a parabolic reflector fixed to said gear for oscillationtherewith and for rotation with said spindle; afeed horn mounted on saidreflector along the axis, thereof; a rack' sleeveextending through saidspindle and mounted for-rotation therewith and; for longitudinalmovement with respect thereto; a. rack mounted on said rack sleeve inmesh. with said gear; a wave guide tube extending throug h said sleeveand connectedwith. said spindle for rotation therewith; means. forestablishing communication betweensaid; wave guide tube, andv the ase. osaid. iecdhorng, a potentiometer mounted on, saidframe,.saidnotentiometer including apair. or fixed. coaxialresistance-coil sect0rs,. a shaft. mounted. coaxial withsaidsectora, apair of con, tact arms. secured to. said. shaft. and. arranged. {$.01traverse. said'sectors; andapinion fastened to. said.

shaft; a potentiometer rack slidably mounted on 762 tion:

said: frame in mesh: with said pinion; a friction chitcl'r mounted on.said; frame inciuding: a fixed. member and a. spring-loaded. rotarymember; a clutch. shaft fiastened to said: rotary member; a. crankfastened to said clutch shaft; a. connection journaled: one end: to the.outer end. of: said crank and pivoted at: its other end. to saidpotentiometer slide rack; a bracket: fixed at one end to, said: skids.rack and having at its. other end. a. rotary but longitudinally fixed;connection; with said sleeite: rack; a generator supported bysaid framein electrical circuit with said: potentiometex; and. means including asecond ChljlGhlfDI simmltaneeuslor rotating saidi spindle, drivin saidclutch shafit. and driving saidi generator or for only driving. said:clutclrshaft.

8s A. scanning unit comprising an antenna, means for rotating said.antenna about; a first means for oscillating said. antenna about asecond axis; rotatable; instrumentalities for; saidmtating and.oscillating means in timed relation; with'respect: to each other, andmeans. operative iii-response to; reversal in. the direction of:rotation of; said. instrumentalities for the motion. ofonB: of saidmeans While continuing: the motion of: the other of said means.

95, A. scamiing. unit comprising: an. antenna. means for rotatnigsaidantenna about a. first.

axis, means for; oscillating said antenna about. a"

second axis, rotatable instrumentalities for driving. said; rotatingand-a oscillating, means in timed: relation with respect to each other;and means responsive to reversal iii-the direction of: rotation of; saidinstrumentalities; for discontinuing rotation. of said. antenna while:continuing its: oscillation; about saidvsecond axis.

16s. A scanning unit comprising; an antenna, means for rotatinasaidantenna about a first axis means for oscillating said' antenna; about asecond. axis, perpendicular to. said: first axis; in.- strumentalities.for. driving said: rotating and oscillating. means timed. relationwithrespect to each otherhmeansoperativezin response to m0ve-- 1 mentoii said" instrumentalities for discontinuing rotation of. said antennawhile continuing itsoscillatiom about, said. second. axis, and: meansfor locating saidsecond axis ma predetermined positiorr upondiscontinuing rotation; of: said antenna.

IL. A; scanning unit, com-prising an antenna, means for: rotating saidantennaabout a first axis, means for oscillating; said antenna about asecond aXisiperpendicu-lar to and intersecting said first axis,rotatable instrumentalities for driving said. rotating means and:rotating said oscillating means; in timed relation with respect to eachother. means responsive to. reversal in the direction Qf-;rotation.,otsaid instrumentalities for discontinuing: rotation of said antenna whilecontinuing itsoscjllationi about said second axis, and; means operableupon such reversal in the direc tionoirotationof said instrumentalitiesfor locating said second axis in a predetermined position;

12; A scanning unit as defined. in claim 10; wherein said. antennaincludes a; parabolic reflecton.

13.. A. scanningas defined in claim r1, wherein said. antenna includes aparabolic refiector.

14. A; scanning; unit comprising a; frame, aspindle icurnalled in. saidframe; a gear mounted on one end. of said. spindlefor rotation about anaxis, perpendicular torthe axis of the spindle, a parabolic. reflectorfixed: to said gear for rota-- therewith, a feed mounted onsaidreflector along the axis thereof, a rack meshing with said gear andmounted in said spindle for reciprocatory movement relative thereto, awave guide communicating with said feed horn, means selectively operablefor simultaneously rotating said spindle and reciprocating said rack orfor simply reciprocating said track without rotational movement of saidspindle, and means for automatically locatin the axis of said gear in apredetermined position upon cessation of rotation of said spindle.

15. A scanning unit comprising a frame, a spindle journalled in saidframe, a gear mounted on one end of said spindle for rotation about anaxis perpendicular to the axis of the spindle, a parabolic reflectorfixed to said gear for rotation therewith, a feed horn mounted on saidreflector along the axis thereof, a rack meshing with said gear andmounted in said spindle for reciprocatory movement relative thereto, awave guide communicating with said feed horn, means selectively operablefor simultaneously rotating said spindle and reciprocating said rack orfor simply reciprocating said rack without rotational move ment of saidspindle, and means responsive to reverse rotation of said spindle tolocate the gear axis in a predetermined position.

16. A scanning unit comprising a frame, a spindle journalled in saidframe, a gear journalled on one end of said spindle for rotation aboutan axis perpendicular to the axis of said spindle, a parabolic reflectorfixed to said gear and provided with a feed horn extending along theaxis of the reflector, a wave guide communicating with the base of saidfeed horn, a rack sleeve mounted within said spindle for reciprocatorymovement with respect thereto, said sleeve being provided with a rackmeshing with said gear, a. potentiometer mounted on said frame andincluding a resistance coil and a contact arm arranged to traverse saidcoil, means responsive to the movement of said rack sleeve foroscillating said contact arm, a generator mounted on said frame, meansfor simultaneously rotating said spindle, reciprocating said sleeve anddriving said generator, and means operable in response to reversal inthe direction of rotation of said spindle for stopping the rotation ofsaid spindle and generator without stopping reciprocating of saidsleeve.

17. A scanning unit comprising a frame, a spindle J'ournalled in saidframe, a reflector swivelled on one end of said spindle for oscillationabout an axis perpendicular to the axis of said spindle, means includinga reciprocating rack for oscillating said reflector, means including areversible motor for reciprocating said rack in response to rotation ofsaid motor in either direction, and means including said motor and anoverrunning clutch for rotating said spindle in one direction inresponse to rotation of said motor in one direction, said clutchautomatically re leasing to discontinue rotation of said spindle inresponse to rotation of said motor in the opposite direction.

18. A scanning unit as defined in claim 5, wherein said clutch is of theoverrunning type.

'I'OMLINSON I. MOSELEY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,231,929 Lyman Feb. 18, 19412,257,320 Williams Sept. 30, 1941 2,400,791 Tolson May 21, 19462.407,310 Lundy et al Sept. 10, 1946 2,408,825 Varian et al. Oct. 8,1946 2,409,183 Beck Oct. 15, 1946 2,410,666 Leck Nov. 5, 1946 2 410,827Langstroth et al. Nov. 12', 1946 2,410,831 Maybarduk et al. Nov. 12,1946' 2,412,631 Rice Dec. 17, 1946- 2,413,187 McCurdy et al Dec. 24,1946 2,437,275 Skene et al Mar. 9, 1948

